1. Field of the Invention
The present invention relates to a liquid crystal display panel, and more particularly, to a liquid crystal display panel, in which a coupling capacitor coupled between a data line electrically connected to a green sub-pixel and a common electrode disposed on a color filter substrate is larger than a coupling capacitor coupled between a data line electrically connected to a red sub-pixel or a blue sub-pixel and the common electrode disposed on the color filter substrate.
2. Description of the Prior Art
Generally, liquid crystal display panels have several advantages, such as light weight, low power consumption, low radiation, etc., and therefore, the liquid crystal display panels have been widely applied to various portable electronic products in the market, such as notebooks and personal digital assistants (PDAs), etc. However, when the liquid crystal display panel is driven, liquid crystal molecules may have permanent deformation due to the liquid crystal molecules being fixed at an angle for a long time. As a result, the liquid crystal display panel cannot refresh frames. Accordingly, in order to avoid reducing display qualities, several polarity inversion driving methods have been applied to drive the liquid crystal display panels.
The polarity inversion driving methods can be classified as frame inversion, row inversion, column inversion and dot inversion, etc. Please refer to FIG. 1, which schematically illustrates a polarity arrangement of sub-pixels when a liquid crystal display panel displays a test pattern by using a column inversion driving method according to the prior art. As shown in FIG. 1, the liquid crystal display panel 10 of the prior art includes a plurality of sub-pixels 12 arranged in a matrix. The sub-pixels 12 disposed in the same column are the sub-pixels used to display red, green and blue in sequence and accordingly denoted by red sub-pixels 12, green sub-pixels 12, and blue sub-pixels 12. Also, a red sub-pixel 12, a green sub-pixel 12 adjacent to the red sub-pixel, and a blue sub-pixel 12 adjacent to the green sub-pixel constitute a single pixel 18. When the liquid crystal display panel 10 is driven by the column inversion driving method, the polarities of the sub-pixels 12 disposed in the same row are alternately arranged with the positive polarity 14 and the negative polarity 16, and the sub-pixels 12 disposed in the same column have the same polarity.
Moreover, when a liquid crystal display panel is tested by displaying a test pattern, the pixels 18 disposed in the same row alternatively display bright and dark, and the pixels 18 disposed in the same column also alternatively display bright and dark. In accordance with the column inversion driving method, the red sub-pixels 12 and the blue sub-pixels 12 that are turned on and disposed in the first row have a positive polarity, and the green sub-pixels 12 that are turned on and disposed in the first row have a negative polarity; on the contrary, the red sub-pixels 12 and the blue sub-pixels 12 that are turned on and disposed in the second row have the negative polarity, and the green sub-pixels 12 that are turned on and disposed in the second row have the positive polarity. The polarities of the sub-pixels 12 are determined by the pixel voltage of each of the sub-pixels 12 being compared to a common voltage. When the pixel voltage is larger than the common voltage, the sub-pixel 12 has the positive polarity, and the pixel electrode is kept at a high voltage level; on the contrary, when the pixel voltage is smaller than the common voltage, the sub-pixel 12 has the negative polarity, and the pixel electrode is kept at a low voltage level.
Please refer to FIG. 2, which illustrates waveforms of a pixel voltage of the red sub-pixel/the blue sub-pixel and another pixel voltage of the green sub-pixel disposed in the first row as shown in FIG. 1. As shown in FIG. 1 and FIG. 2, a number of the sub-pixels 12 having the positive polarity 14 is larger than a number of the other sub-pixels 12 having the negative polarity 16 in the same row; that is data signals Vd provided to the red sub-pixels 12 and the blue sub-pixels 12 are kept at the high voltage level, and data signals Vd provided to the green sub-pixels 12 are kept at the low voltage level. Under this condition, the common voltage Vcom may be affected by the data signals Vd provided to the red sub-pixels 12 and the blue sub-pixels 12, and shift toward the high voltage level. Thus, a pixel voltage difference for driving the red sub-pixels 12/the blue sub-pixels 12 is reduced, and a pixel voltage difference for driving the green sub-pixels 12 is raised. Consequently, the red sub-pixels 12 and the blue sub-pixels 12 display low gray scales, and the green sub-pixels 12 display high gray scales. As a result, when the liquid crystal display panel 10 is tested to display the test pattern by using the column inversion driving method, the liquid crystal display panel 10 may display greenish frames. Accordingly, to solve the greenish problem of frames is an objective in industry.